2010 Summer Records from the South Dakota State Climatologist

BROOKINGS, S.D. – Nine of South Dakota’s data-collection stations set records for precipitation, making 2010 one of the wettest summers ever.

That’s according to South Dakota State University professor and Extension State Climatologist Dennis Todey, who said most of the record-setting wet stations were in the southeastern part of the state.

“We saw the highest recordings for precipitation in the southeast. Marion was the ‘big winner’ with 26.32 inches of rain for the summer, and that total is more than one inch higher than their annual average total precipitation,” Todey said. “Northwestern South Dakota also was very wet for summer. Camp Crook recorded 10.74 inches and Lemmon recorded 13.58 inches. Both came in as the third wettest summers on record for those areas.”

Todey said that at least 15 of the statewide stations recorded precipitation amounts that put 2010 in the top 10 wettest summers on record.

“In comparison, these precipitation amounts exceeded amounts from two other very wet summers, 1993 and 1944,” said Todey. “The Wessington Springs station has already broken their annual record precipitation, and that several others are well within reach of setting new records with more than three months of the year left.”

Not all of the state saw excessive precipitation. North central South Dakota, including the areas around Selby, Roscoe, and Eureka, experienced much drier conditions that put their gathered data into the top 10 driest summers.

“Selby was the worst receiving only 3.07 inches of rain, just off their record of 3.01 inches in 1973,” Todey said. “A few other stations in the north central area, along with some in southwestern South Dakota, recorded levels that put them in the top 20 driest summer seasons.”

Todey said the lack of rainfall in those areas led them to their inclusion on the U.S. Drought Monitor map during August when dry conditions finally impacted crops in the area.

In terms of temperature, Todey said the eastern two-thirds of the state saw warmer-than-average temperatures, while the farthest western part of South Dakota was slightly cooler than average.

“Only a few near records were set in terms of temperature, and a few places in the northeast were in the top 20-35 warmest summers,” said Todey. “The two towns that saw the most significant extremes were Webster, where they recorded their 12th hottest summer, and in Roscoe, where the ninth hottest summer just ended.”

Todey said much of the state’s warmth during the summer came from very high overnight temperatures.

“The average low temperatures were much higher than average over most of the eastern part of the state,” Todey said. “In some cases, it was by as much as 3-4 degrees F. Seventeen locations had low temperatures that registered in the top 10 warmest for the summer.”

Three stations – Webster, Canton and Roscoe – had average low temperatures higher than any past summer.

“These conditions were related to the amount moisture in the air, because when we have high dew point temperatures overnight, it keeps the lows from dropping very far,” said Todey. “Extremely moist conditions continued through the summer and helped keep overnight low temperatures higher than they would be in drier air.”

Hail was another notable 2010 summer weather category, and a July 23 storm near Vivian set a national record, Todey said.

“The stone from that storm was preserved and confirmed as the largest diameter and heaviest hailstone ever recorded and documented in the U.S.,” said Todey. “The stone measured at 8 inches and one pound, 15 ounces.”